Pump jack



June 3, 1941. K, T, BLAKELEY 2,244,607

' PUMP JACK Filed Deo. 9, 1940 2 sheets-sheet 2 nnnnn Sme/wm Patented June 3, 1941 UNITED STATES APATENT OFFICE Application December 9, 1940, Serial No. 369,345

(Cl. i4- 31) 6 Claims.

This invention relates to pump jacks but may be utilized in other machinery where it is de-v sired to convert rotary motion into reciprocating motion without undue hammering at the ends of the reciprocal strokes. Y

An object of the invention is to provide an improved pump jack of simplified construction, in which rotary motion is converted into reciprocating motion smoothly and without undue noise or friction.

A further object of the invention is to provide an improved pump jack in which lthe arrangement of parts is such as to avoid undue wear.

The invention consists in the novel construction, arrangement, and combinations of parts, as hereinafter more specifically described and claimed.

Two sheets of drawings accompany this specication as part thereof, in which likeV reference characters indicate like parts throughout.

Figure 1 is a front elevation of the improved jack showing the head at the end of the up stroke;

Figure 2 is a tranverse vertical cross section taken on line- 2 2 of Figure 1; A

Figure 3 is a fragmentary front elevation of the upper end of the head shown approaching the bottom of a stroke;

Figure 4 is a view similar to Figure `3 as the heads starts the up stroke;

Figure 5 is a fragmentary enlarged view of the bottom part of the pump head at the end of its up stroke;

Figure 6 is a horizontal cross sectional view taken on line 6 6 of Figure 4.

In accordance with the present invention the improved jack comprises a frame consisting of a base I with vertical spaced parallel columns 2, each having on its inner face a track 3. The columns 2 are preferably spaced by transverse frame members 4 to assure their alignment.

Between the columns 2 is slidably positioned a head 5 having on its parallel side edges grooves 8 adapted to receive tracks 3. The head is engaged by any conventional means with the pump rod 9. The head 5 is provided with an elongated opening having spaced parallel side walls 6 6 connected by curved end walls 1 1 and all the inner walls of this opening are provided with rack teeth and constitute an endless rack.

On the front and rear faces of the head are peripheral flanges 20 constituting guide tracks. These tracks are interrupted on each side near the top and bottom by cross-over clearances 2| for a purpose hereinafter explained.

A transverse frame member I0 is carried by the columns 2 2, provided with journals for a drive shaft II, upon which is fixedly securedy a gear I2 and upon which is also pivotally mounted a rock frame I3 which, as illustrated, consists of two spaced strap members, positioned one on either side of xed gear I2, and between which are journaled gears I4 I5, and I6. It will be noted that gear I6 engages directly with iixed gear I2 and also with one side of the endless rack,fwhi1e gear I4 at the opposite end of rock frame I3 engages the opposite side of the rack and is'driven through intermediate gear I5 from fixed gear I2. It will thus be seen that the rack engaging gears I4 and I6 are both driven from Xed gear I2, but in opposite directions. It will further be noted that the rock frame I3 is longer than the distance between the parallel sides of the rack by reason of which it will always assume an oblique position with respect to those parallel sides of the rack with one or the other of the rack engaging gears in advance of the other rack engaging gear Pivotally mounted on the outer ends of rock frame `I3 are rollers I 8 adapted to engage the outer face of flanges 20 and thus secure gears I4 and I6 in engagement with the rack.

By reason of the construction thus described it will be apparent, reference being had to Figures 3 to 5, that the head being at the end of its downward stroke, as illustrated in Figure 3, gear I6 being in advance will be forced from the side of the rack as gear I4 starts to traverse the upper curved portion of the rack, the guide rollers I8 adjacent gear I6 passing through the adjacent cross over 2l and thus rocking the rock frame I3 until gear I4 engages the opposite side as shown in Figure 4 whereupon the head will commence its up-stroke. In Figure 5 the head is shown completing the end of its up-stroke with gear I4 again engaging the side of the rack, the adjacent rollers I8 having passed out through adjacent cross-over clearances 2l.

It will be noted that the rock frame I3 is held constantly in position with respect to the head by means of rollers I8 and guide flange 20 at one end or the other of the rock frame and during the greater part of the vertical stroke of the head by the rollers on both ends, but that the cross-over gaps 2I provided in flange 20 permit the rocking of the rock frame at each end of its stroke.

Various modifications will readily suggest themselves to those skilled in the art and it will be apparent that the present invention, while shown applied specifically to pump jacks may be of equal utility in connection with Various other machinery, where the same or similar problems are presented.

Having thus fully described my invention, I claim:

1. A frame, a member reciprocable in the frame having an interior endless rack comprising spaced parallel sides connected at each end with curved parts, a shaft extending within and perpendicular to the plane of the rack, a driving gear fixed to the shaft, a rock frame pivotally mounted on the shaft, and gears mounted on said pivoted frame driven from said fixed gea'r and including two oppositely disposed gears adapted to engage the opposed parallel rack sides and to be driven in opposite directions, and means for maintaining the rock frame in operative association with the frame at all times.

2. An elongated endless rack having spaced parallel sides and curved ends with teeth formed on the inner face, and means for reciprocating the-rack comprising a shaft passing Within the rack, a frame pivoted on the shaft, a gear xed on the shaft ,and a plurality of gears pivotally mounted onthe frame including` two driven gears adapted to engage the opposite parallel sides of the rack and rotate in opposite directions. Y, l

A34A pump jack comprising a base and two parallel vertical frame members each having a track on its inner face, a reciprocating head slidablyl engaging said` tracks and formed with an opening having spaced parallel side walls and curved top and bottom walls, said inner Walls providedwith teeth to constitute an endless rack, a shaft extending between and supported from the frame members and passing through the opening in the head, a gear fixed on the shaft, a rock frame pivoted on the shaft, a plurality of gears rotatably mounted on the frame including two driven gears adapted to engage the opposite parallel rack Walls of the head and to be rotated in opposite directions, means for maintaining the rock frame in operative relation to the head and means for connecting the head with the pump rod.

4; Means for ytranslating rotary motion into reciprocating linearV movement comprising a shaft, a gear fixed on the shaft, a rock frame pivoted on'the shaft, a plurality of gears rotatably mounted on 'the rock frame including gears at the ends of the rock frame and on opposite sides of the shaft arranged to be driven in opposite directions by said gear xed on the shaft, an endless rack surrounding said rock frame including two parallel straight sides connected by curved end parts, said end driven gears arranged to engage the parallel sides of the rack simultaneously and said frame adapted to be rocked at the ends of said straight sides, a guide track on the rack having cross-over spaces at top and bottom and rollers on the ends of the rock frame engaging said track.

5. A frame, a member reciprocable in the frame formed with an opening having parallel straight sides connected by curved ends, the inner Walls of said opening formed with teeth constituting an endless rack, a shaft passing through said opening, a gear fixed on the shaft, a rock frame longer than the distance between the straight sides of the rack, a plurality of gears rotatably mounted on the rock frame including a gear at each end and on opposite sides of the fixed gear arranged to be driven in opposite directions by said gear and to engage the opposite straight sides of the rack, and cooperating means on theV frame and rock frame to maintain same in operative relation.

6. A pump jack comprising a base and two spaced parallel frame members each having Va track on its inner face, a reciprocating head slidably engaging said tracks and formed with an opening having parallel side Walls and Vcurved top and bottom walls, said inner walls provided with teeth to constitute an endless rack, a peripheral guide track on said head having spaced cross-over gaps, a shaft'extending through the opening in the head,l journals for the shaft carried by the frame, a gear xed on the shaft, a rock frame longer than the distance between the parallel rack sides pivoted on the shaft, gears pivoted on the rock frame on opposite sides of the xed gear, one of said gearsmeshed with the xed gear and the raclg on one side and another gear meshed with the rack on the opposite side and through an intermediate gear with the fixed gear whereby .the rook engaging gears will be driven from the fixed gears in opposite directions and rollers on thev rock frame adapted to engage the peripheral guide track and maintain said rock frame in constant operative relation to the head While permitting the rocking of the rock frame. l Y

' KARL T. BLAKELEY. 

